Recovery of elemental sulfur



y 15, 1952 s. L. NEVINS ET AL 2,603,464

RECOVERY OF ELEMENTAL SULFUR Original Filed Jan. 25, 1945 222 FIG. 2,

r55 190 292 A 183 I 19/ 175 Patented July 15, 1952 Gilliam, Jr.," Stamps, Ark., assignors, by mesne assignments, to, The Fluor Corporation, Ltd.,a

corporation of California Original application January 25, 1945, Serial No.

Divided and this application March 28, 1949, Serial No. 83,906

2 Claims.

, l This invention relates to the recovery of elemental sulfur and more particularly to apparatus for condensing vapor phase sulfur.

This application is a division of our copending application Serial No. 574,607, filed January 25. 1945, now Patent No. 2,534,792v of December 19, 1950. r

Briefly, the invention comprises vapor phase sulfur condensing apparatus which includes a plurality of vertically spaced, substantially horizontal baffles, horizontally offset from each other.

The waste acidic gases separated in the various extraction processes employed in the manufacture of commercial natural gas, coke oven gas, and petroleum products, normally contain sulfur in the form of hydrogen sulfide, and in addition thereto, usually contain water vapor and various gaseous materials in the form of carbon dioxide, carbon monoxide, and hydrogen, and in many instances sundry hydrocarbons such as methane, ethane, and propane. Again, in some waste acidic gases are found such sulfur compounds as, hydrogen sulfide, sulfur dioxide, carbonoxysulflde, carbon .disulfide, and in certain instances, alkylsulfides, together with gaseous paraffmic and oleflnic hydrocarbons, water vapor, carbon dioxide, and

hydrogen.

Certain chemical treating plants may produce waste gases containing recoverable amounts of sulfur compounds, usually mixed or combined with impurities. For example, plants for the manufacture of carbon disulfide from sulfur and methane, may throw off waste gases containing sulfur vapor, hydrogen sulfide, methane, and other hydrocarbons. a

, Attempts have been made previously to recover commercially profitable yields of elemental sulfur from such waste acidic gases but without success, since the reactions which are reputed to occur in the treatment of hydrogen sulfide gases are not realized, which may be explained in part by reaction disturbances caused by other gaseous 1mpurities and materials which the waste acidic,

gases contain. It has therefore been the common practice .to burn such waste acidic gases under iboilers or in flare towers since such waste acidic gases have an obnoxious odor and are lethal in character and hence cannot be discharged into the atmosphere.

An object of this invention is to provide an unproved apparatus for the treatment of waste acidic gases containing sulfur compounds whereby elemental sulfurof high quality maybe recovered in a highly economical and pract cal manner; I

, Another objectof this invention is to provide an. improved apparatus for the treatment of waste acidic gases containing sulfur compounds whereby the obnoxious and toxic constituents may be substantially completely removed therefrom, thereby providing a resulting effluent gas unharmful to animal and plant life;

Another object of this invention is to provide a highly economical and efficient apparatus for the recovery of elemental sulfur from gases cast off from refining, gas treating, .and chemical opera tions. I

Other objects and advantages of this invention will be more readily understood and compre: hended from the following disclosure. i

For ready comprehension of the invention, the chemical and physiochemical factors involved in the operation, and the design and construction of the apparatus, there isshown in the accompanying drawing a series of embodiments of physical structure in which:

Fig. 1 illustrates the condensing apparatus of the present invention shown partly in elevation.

and partly in vertical cross-section; and

Fig. 2 is a fragmentary verticalcross-section taken on line 2-2 of Fig. 1.

Similar reference characters refer to similar partsthroughout the several views of the drawing and specification.

This invention. is directed to condensing 'or scrubbing apparatus WhiCh'iS particularly useful insystems employed for'l'the recovery of e1emental sulfur from waste acidic gases containing compounds such as hydrogen sulfide, etc. The apparatus of the present invention areparticularly useful in the sulfur recovery system described in our aforementioned Patent No. 2,534,-

Referring now more particularly to the drawing, there is indicated at reference numeral 110 a :sulfur condensing or scrubbing tower which is cappedby a housing I'IL- -The tower, I110 ispref-- verably built'iup from ;a series of bafiie. sections I12 arranged in superimposed [relationship and capped by a distributing section I82 at the-top thereof. Each of the baffle sections I12 comprise a tubular enclosing wall'built up from steel plate which may be either round or polygonal in crosssection. The baflle sections'l'l2' and the distributing section I-82, as shown in Figs. 1 and 2, have enclosing walls which are approximately rectangularv in cross-section. The upper and lower ends of each section "I12 may b'e'provided with outwardly flared flanges: I13 by means of thereof-[to which' a s'eries of inclined ladder bars I14, I75, and I19, are attached. It will be noted by referring more particularly to Fig. 2 that the ladder bars I74 and I16 are inclined in one direction' while the intermediate bars l'li are inclined in the opposite direction. A series of horizontally spaced extending baflies such. as .bars 98, extend between and are secured to the. series ofladder bars I14, I75 and I76 thereby forming a series of superimposed tiers of parallel horizontally spaced inclined grills. The bafiles 98' may have anangular L-shaped cross-section and are preferably formed of corrosion resistant metal such as stainless steel. It will be noted that the baffles 98 are.

arranged in staggered relationship so that droplets or small streams of liquid falling-on the upper'bars will successivelyfall against successive baffles 93- as the liquid stream or droplets move downwardly through the successive bafile sections I12. of. the tower I19. 1

The distributing section. I82 has the same crosssectional contour as the. bailie sections I12, and is provided with outwardly flared flanges I83 at each end. thereof. The lower flange I83 is bolted or secured to the upper flange I73 of the topmost bafile section I12.

The liquid line 96 is connected to a horizontally extending. distribution pipe I81 which enters into thetop Part of the distribution section I82. To the distribution pipe I81 is connected a series of branched. pipes I83 each having a downwardly projecting row of nozzles I190 which direct the cooling liquid downwardly at various spaced points within the upper end of the distribution section I32. The inner end of the distribution pipe I87 may be supported by a bar I89 fixed at the ends thereof to the opposite side walls of the distribution section I82.

A seriesof relatively closely spaced inclined metalbafiie plates I88 extends transversely across the interior of the distribution section. Immediatelybelowthe series of metal bafile plates I96 is another series of metal baffle plates I 89' in- .clined in the opposite direction. The upper and lower series of bafie plates I95 and I86 are fixed to supportingbars Ifidwhose ends are secured to the oppositeside walls of the distribution section I82, Directly below each row of nozzles I96 is a shallow receiving trough I9I into which the condensing liquid from the nozzles I 90 may drop. Each trough I9I has ajplurality of discharge nozzles I92 in the bottom'thereof through which the condensing liquid may pour out. It will be noted by referring to Fig. 2that the upper and lower series of bafiie plates I85 and I 96' are cut away as indicated at 193A directly below each 'row' of nozzles IBBfso as to permit the coolant v liquid" to flow from nozzles I90 directly into the receivingtroughs I9I without interference from the ba fii'e plates I36 and its. It will be appreci ated that the baiiie'plates lts and 585' serve to provide surfaces upon which the sulfur vapors may condense andupon which sulfur spray will formf into droplets which will drip downwardly from trough I 9! through nozzles I92 in the tower.

I Directly'below each row of nozzles I92 is a splash'b-oard I931 supported upon angle bars I9 3 whose ends are secured to the opposite side walls of; the distributionsection I82; The coolant liquid'. discharged from nozzles I92 will splash 4 against the splash boards I 93 and thence further splash against the series of baiiies 98 in the successive bafile sections I12. Thus the coolant liquid discharged from the nozzles I92 will be broken into small rain-like droplets which are agitated and distributed uniformly, within the tower as they move downwardly toward the bottom thereof.

The scrubbing unit I'IIl is provided with a tanlr 9! at the basethereof in which the coolant 1iq uid, preferably molten sulfur; is collected and contained. The tank 9| is built up of steel plate and is provided with a bottom wall 200 and enclosing side walls 2!, above which the tower I'IB is mounted. The enclosing side wall 2M may be reinforced bysuitable frame members 293 and is divided internally by a partition wall 204 into a cooling section 205 and a pump sump section 206. The tank 9| may be provided with a cleanout door 2 I 8 provided at the lower end of the enclosing side wall 2! thereof. The coolant liquid or molten sulfur flows from the cooling section 295 under thedivision wall 204 into the pump sumpsection 295.. The cooling section 205 contains coolingcoils-QZ joined at the ends thereof to an entrance header 29'! and a discharge header 298. Cooling water enters the entrance header. 291 by a water linev 93 and is discharged through outlet pipe 2il9 connected to the discharge header 298. A steam'line as may also be connected to the inlet header 291 to heat the coils 92,.the steam being removed through an outlet line 2 I 9 connected to the discharge header The pooled liq id, such asmolten sulfur, flowing into the pump sump section 296 is pumped by apump upwardly through the vertical line 99 which is connected at the. upper end thereof to the distribution pipe 3 1. The pump 95 driven by a motor 95' extends into the liquid contained in the pump sump section 206.

The reaction gases containing the sulfur vapors to be, scrubbed out enter the lower end of the scrubbing unit Il'd through a suitable fitting 220 connected to the supply conduit 99 at a temperature approximately 270 to 450 F. The reaction gases with the entrained sulfur vapors rise upwardly through the tower I10 in counterfiow to the 'downwardly splashing droplets of liquid sulfur distributed throughout the tower in small droplets by the splash plates I93 and bafiles 98.

Sulfur vapors entrained in the reaction gases are thus'washed out or condensed by the downwardly cascading stream of liquid sulfur, which base temperature of 260 to 270.F. 7

The inclined vbafile plates I86 and IE9 provide spray removal surfaces on which any remaining vapors not removed from the reaction'gases may be caught. The scrubbed reaction gases, free of sulfur vapor, pass out through the discharge port 22I at the upper end of the housing I'II of the scrubber unit. The housing III of the scrubber unit may be provided with access ports 222 which provide access to the interior of the tower.

7 The stream of moltensulfur pumped into-the upper end of the distribution section by'the pump 99 through the supply line 96 cascades downward and is joined by additional molten sulfur. roduced by the condensation of the sulfur vapors entrained in the'reaction gases passing upwardly through the tower I10. 7 This molten sulfur collects in the cooling sectioniile Where itis cooled O a temperature of approximately 26o F.

temperature.

approximately 80 F. and leave the coils through the water discharge line 209 at a temperature of approximately 120 F. Should it be desirable to heat the sulfur contained in the pump sump section 296 and the cooling section 205 as during periods of shutdown, steam may be passed through the cooling coils 92 and admitted through the steam line 94 and discharged through the steam line M0. The pump 95 operates continuously during operations and transfers the molten sulfur from the pump sump section 206 to the distribution system within the section. I82. The molten sulfur accumulating in the pump section 206 may be drained off continuously or intermittently through the Weir line 99 to a receiving vessel, which if desired may be suitably heated to permit ready removal of the elemental sulfur in liquid form.

In order to secure maximum liquefaction of the sulfur vapors entering the tower I it is desirable that the reaction gases discharged from the tower 110 through outlet 22! be held atapproximately 260 ing from the tower should be as close to the freezing point of sulfur as possible, and preferably only sufiicientlyabove the freezing point to prevent the solidification of sulfur in the upper part of the tower and ducts leading from the tower. I

In the tower I10 due to the direct contact of the cooled molten sulfur with the entering gas,

'. the temperature of such gas is rapidly reduced.

In passing upwardly through the tower the gases are substantially cooled and are discharged at a temperature of about 260 F.

It is found that when operating the process in the manner described, the gases discharged from the top of the scrubber unit I10 are substantially denuded of free sulfur and contain but a small amount of combined sulfur. If desired, this gas may be discharged from the system.

The gases and vapors uncondensed in the In a typical operation the water may enter the cooling coils 92 at a temperature of F., that is to say, the gas escapscrubber unit I83 pass out through outlet 22!.

This eilluent gas contains substantially all the carbon dioxide in the waste acid gas feed, the nitrogen from the air, and the water vapor in the feed and produced during the reaction, to gether with the indicated minor amounts of hydrogen sulfide and sulfur dioxide which is so small that the effluent gas is substantially free of obnoxious odor and accordingly may be discharged into the atmosphere.

While preferred embodiments of the invention have been described, it is understood that these are given didactically to illustrate the fundamental principles involved, and not as limiting the useful scope of the invention to the particular embodiments illustrated.

for said distributing section, a plurality of superimposed tiers of parallel horizontally spaced, inclined grills consisting of horizontal baffles of substantially L-shaped cross section within each of said bailie sections, the incline angle of one tier of grills being opposite to that of=a vertically adjacent tier of grills, said bafiies in each grill being horizontally offset and spaced apart a substantial distance to allow for passage of gases, at least two series of horizontally spaced inclined baflie plates within said distributing section, said first series disposed below said second series ofplates, a series of troughsdisposed beneath said baille plates, said condensing fluid inlet comprising a series of nozzles disposed above said baflle plates and adapted directly to charge said. troughswith condensing fluid, a plurality of apertures in said' troughs, a series of splash board disposed under said apertures, a condensate sump disposed beneath said baflle sections, cooling coils within said sump, an outlet for said sump, and a pipe interconnecting said sump outlet to said condensing fluid inlet. 2. In a condensing tower including a gas inlet and condensate outlet in the lower portion of said tower, a gas outlet and a condensing fluid inlet in the upper portion of said tower, a distributing section disposed below said condensing fluid inlet and having at least two series of horizontally spaced inclined bafile plates, said first series disposed below said second series of plates, a series of troughs below said second series of baflle plates, said condensing fluid inlet comprising a series of nozzles disposed above said bafile plates and adapted directly to charge said troughs with condensing fluid, a plurality of apertures in said troughs, and a series of splash boards disposed under said apertures; a plurality of superimposed tiers of parallel horizontally spaced inclined grills consisting of horizontal bafiles of substantially L- shaped cross section, the incline angle of one tier of grills being opposite to that of a vertically adjacent tier of grills, said baflles in each grill being horizontally offset and spaced apart a substantial distance to allow for passage of gases.

SAMUEL L. NEVINS.

JAMES s. GILLIAM, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENT 

2. IN A CONDENSING TOWER INCLUDING A GAS INLET AN CONDENSAE OUTLET IN THE TOWER PORTION OF SAID TOWER, A GAS OUTLET AND A CONDENSING FLUID INTLET IN THE UPPER PORTION OF SAID TOWE, A DISTRIBUTING SECTION DISPOSED BELOW SAID CONDENSING FLUID INLET AND HAVING AT LEAST TWO SERIES OF HORIZONTIALLY SPACED INCLINED BAFFLE PLATES, SAID FIRST SERIES DISPOSED BELOW SAID SECOND SERIES OF PLATES, A SERIES OF TROUGHS BELOW SAID SECOND SERIES OF BAFFLE PLATES, SAID CONDENSING FLUID INLET COMPRISING A SERIES OF NOZZLES DISPOSED ABOBVE SAID BAFFLE PLATES AND ADAPTED DIRECTLY TO CHARGE SAID TROUGHS WITH CONDENSING FLUID, A PLURALITY OF APERTURES IN SAID TROUGHS, AND A SERIES OF SPLASH BOARDS DISPOSED UNDER SAID APERTURES; A PLURALITY OF SUPERIMPOSED TIERS OF PARALLEL HORIZONTALLY SPACED INCLINED GRILLS CONSISTING OF HORIZONTAL BAFFLES OF SUBSTANTIALLY LSHAPED CROSS SECTION, THE INCLINED ANGLE OF ONE TIER OF GRILLS BEING OPPOSITE TO THAT OF A VERTICALLY ADJACENT TIER OF GRILLS, SAID BAFFLES IN EACH GRILL BEING HORIZONTALLY OFFSET AND SPACED APART A SUBSTANTIAL DISTANCE TO ALLOW FOR PASSAGE OF GASES. 